Ship to Ground Communications
The next higher organizational level for the overall communications system involves contact and information exchange between the starship and planetside personnel and remote equipment. Communications external to the spacecraft are routed from the main computers to the radio frequency (RF) and subspace radio system nodes. While the term "radio" is something of an anachronism, since Starfleet communications more often than not involve visual information, it nevertheless continues to describe the basic function of the system. Normal radio frequencies are set aside as backups to the primary subspace bands, though RF is in continued use by numerous cultures maintaining relations with the Federation, and Starfleet vessels must sometimes rely on this older system when subspace bands prove unusable due to stellar or geological phenomena, or when hardware difficulties arise with either the host or remote sides. Such space-normal radio communications are, of course, restricted by the speed of light, resulting in severe time and distance limitations. INSTALLED HARDWARE The RF section consists of a network of fifteen triple redundant transceiver assemblies cross-connected by ODN and copper-yttrium 2153 hardlines and linked to the main computer comm processors. All are partially imbedded within the structural hull material at degree and distance intervals about the starship for maximum antenna coverage and manageable antenna timesharing loads. Each transceiver assembly is a hexagonal solid measuring three meters across the faces and one-half meter in thickness. Each consists of separate voice and data subprocessors, eight six-stage variable amplifiers, realtime signal analysis shunts, and input/output signal conditioners at the hull antenna level. RF section power is obtained from Type III taps from the electro plasma system. The basic limitations of the RF section stem from the c velocity limit, and a normal useful range at moderate power on the order of 5.2 Astronomical Units (A.U.). RF frequencies directed through the steerable central component of the main deflector can extend the useful range to some 1000 A.U., though no practical applications of this power have yet been demonstrated. The subspace transceiver specifications, in proportion, are roughly akin to the warp propulsion system being compared to its less powerful impulse cousin. Approximately one hundred times more energy is required to drive voice and data signals across the threshold into the faster subspace frequencies, and even when applied to relatively short distances, the transmission reliability climbs dramatically. As with the RF section, small transceivers such as the standard subspace transceiver assembly (STA) in the personnel communicators need not emit great amounts of power if the large transmitters and receivers remain on the starship. A series of twenty medium-power subspace transceivers are imbedded within the starship hull at various locations to provide communications coverage similar to that of the RF units. Each triple redundant device is contained within a trapezoidal solid measuring 1.5 x 2 meters by 1 meter in thickness. The system is powered by Type II electro plasma system (EPS) taps with a total maximum power load across the twenty nodes of 1.43 x 102 MW. Each transceiver consists of voice and data processors, EPS power modulation conditioners, subspace field coil subassemblies and directional focusing arrays, and related control hardware. Signal handoff from the optical data network is done with a combination of realtime and sequence anticipation Al routines for maximum intelligibility, given the FTL nature of the outgoing and incoming subspace signals. APPLICATIONS Communications between the starship and a destination typically 38,000 km to 60,000 km away from the antennae are handled by the above-mentioned radio systems. Situations encountered cover a broad range, but most notably include discussions with planetside governments, communication and control of Away Team operations, local and regional crisis management, data collection from remote and active occupied research stations, shuttlecraft departure and approach terminal guidance, and Starfleet search and rescue. The subspace transceiver network is the active system linked to the transporter for personnel locator and coordinate lock-on functions. A minimum of three transceivers covering a given portion of the spacecraft sky coverage must be available for reliable transporter lock. The maximum reliable distance for routine transport is 40,000 km, owing to the median matter stream blooming tolerance of 0.005 arc-seconds, though subspace communications by the medium-power network can extend to some 60,000 km. Normal contact with the starship, if externally initiated, is divided into two basic types: Starfleet personnel, especially those persons directly assigned to the ship, and non-Starfleet agents. Away Team members will call directly to the Bridge or other active departments during the course of their work. Normal contact from outside agents will be held by Security for presentation to the captain or other senior officers. Emergency transmissions will usually be passed without computer delay for appropriate action. Standard encryption/decryption, plus enhanced security encryption protocols, are handled by FTL processors within the main computers. Starfleet encryption algorithms are rotated and updated on a random schedule. Multiple private key portions are retained with the starship computers, and the public portions are transmitted to Starfleet-issue hardware, such as handheld instrumentation, communicators, personal access display devices, and other pieces of expendable gear vulnerable to possible capture by Threat forces. Calling for a secure channel on either the spacecraft or remote side will be detected by the main computer, which will place higher encryption schemes in standby mode to await confirmation by command personnel. With certain non-Starfleet subspace transmission protocols, particularly for data burst receiving, protocol matching delays may be forced by the computer until matrix translation values are calculated and applied in realtime. True Starfleet burst modes, as designed into the standard and medical tricorders, allow rapid emergency transmissions of stored information via the subspace system. Single antenna coverage is acceptable, though the physical layout of the antenna groups assures at least two arrays will be visible if the spacecraft is in line-of-sight of a transmitter. Category:Communications Category:Engineering Category:Operations Category:Ship Systems